The present invention relates to a shoe sole and a shoe. In particular, the invention relates to a shoe sole including a front portion and a heel that differ greatly in hardness.
A conventional shoe sole includes an outsole and an insole. The whole of the outsole is integrally molded out of uniform elastic material. The outsole includes a bottom and a rim, which rises from and extends around the bottom. The insole is bonded to the top of the rim. A shoe sole of this type is disclosed in Japanese Utility Model Registration No. 3,056,650, for example. The waist of the outsole of the disclosed sole includes a first middle plate, a second middle plate and a third middle plate that are formed inside the outsole rim. The first and third middle plates are positioned on the front and rear sides respectively of the second middle plate. The middle plates rise from and extend across the outsole bottom. The first and second middle plates have air (vent) openings formed through their tops. The rim and the first middle plate define a front cavity, in which a number of front plates rise from and extend across the outsole bottom. The front plates have air (vent) openings formed through their tops, and incline forward. The outsole bottom has a hole formed through it between the second and third middle plates. The top of the hole is covered with a fabric that is air-permeable and not water-permeable.
When the wearer""s foot applies a high pressure on a front portion of the insole, the cavity of the outsole is compressed and deforms. The air in the compressed cavity under the insole is discharged through the air openings of the front, first middle and second middle plates and the bottom hole between the second and third middle plates out of the shoe. The sole is effective as a means for discharging the air in the shoe by utilizing the compressive performance of the elastic material. The inclining front plates improve the cushioning property of the shoe, making the shoe comfortable.
Because the sole is integrally molded out of uniform elastic material, its hardness is uniform. A front portion of the outsole rim of the integral sole is so hard that the outsole cavity is less compressible. This prevents sufficient discharge of the air in the cavity. A front portion of the integral sole is so hard that the shoe is not sufficiently comfortable.
The object of the present invention is to provide a shoe sole that improves the suction into and exhaust from a shoe and makes the shoe comfortable.
A shoe sole according to the present invention includes an outsole molded integrally out of rubber. The top of the outsole is covered with an insole. A rim is formed around the bottom of the outsole. A first middle plate, a second middle plate and a third middle plate are formed in the waist of the outsole and widthwise partition the inside of the rim. The first and third middle plates are positioned on the front and rear sides respectively of the second middle plate. The first and second middle plates have air openings formed through upper portions thereof. Front plates are formed in the cavity surrounded by the rim and the first middle plate. The front plates have air openings formed through upper portions thereof. The cavity is covered with the insole to form a space. The outsole has a hole formed through the bottom thereof between the second and third middle plates. The top of the hole is covered with a fabric that is air-permeable and not water-permeable. The outsole includes a front portion and a heel, which have different compounding ratios between the bulking and softening agents of the material for the outsole such that the front portion is considerably lower in hardness than the heel.
Thus, the front portion of the outsole is greatly lower in hardness than the heel of the outsole so as to be elastic and more flexible, making the cavity in the front portion more compressible. This improves the air suction and exhaust efficiency of the space formed in the cavity covered with the insole. This also improves the cushioning property of the shoe, making the shoe very comfortable.
And the cushioning property depends on the front portion""s softness not for on the air-tube. So shoe keeps a long life of the cushioning property without worrying about leakage of air.
The insole may have an air hole formed therethrough over the outsole cavity. Air can be discharged through this hole as well. This makes it possible to improve the exhaust efficiency and the suction.
The insole may include an upper layer made of continuously foamed material. The use of this layer in a shoe makes the shoe more comfortable, without lowering the suction and exhaust efficiency.
Men""s and women""s shoes may each be made with a sole according to the present invention. The use of this sole makes each shoe not liable to be stuffy, and makes each shoe more comfortable.